Caliber...bullet...brass selection ?

[Flexmoney]

I am hoping that some of the experienced shooters that have been posting here could share some of that experience and insight (perhaps some voo-doo ).

Maybe even get a little technical ?!!?

I see where Bruce posted that he runs 115g @ 1150fps. Whenever I see 1150fps I always think of that as a magic number. It is (depending on conditions) going to spit out bullets that are just under the speed of sound. Now, I don't have any experience in this other than pulling from my Sierra manual...where they did do testing. They have pretty graphs and such that show that bullets become unstable as they are passing through the speed of sound.

Why not a 40/10mm bullet? Not accurate enough? Too slow for the mover? What about a 0.400 bullet at 135g? Does it get too short and stubby to have enough bearing surface (to sit nice in the brass? to engage the barrel...throat...rifling?)

OK...back to 38/9... anything about the shape that makes a difference? 95g? 108g 115g? 124g?

Super brass? Super-comp? 38TJ? 9x23? Does any of that hold the bullet better? Does any of it hold the chamber or extractor better?

Any random musings would be appreciated.

[longbarrel]

You can use 40's or 45's or whatever but you only have to make minimum power factor of 120,000. Most people use

115 JHP's in .355. At first I experimented with many combinations ( and occasionally still do) and ended up back to 115 JHP's in 38 Super or super comp and a 1911.

You need to keep your projectiles at least 1000 fps to be able to keep your leads on the mover target for best results.

( I shoot metallic sight class) I run 115's at 1100 fps. Occasionally I use 125's at 1000 to 1025 with just slightly less accuracy at 50 yds. 2.5 inch 6 shot groups compared to 2 inches or less with the 115's.

Using a revolver is never a poor choice and I do use one about 50% of the time. Again the results you are after are the same. 100% function and good accuracy. You only have 192 shots and each one is worth 10 points.

The smaller the bullets the less the cost. Their is really not a good reason to use anything bigger. Also, 9mm is the minimum caliber allowed.

You can see many combinations of guns at the NRA Bianchi Cup. I love it.

couple of test 6 shot groups.

Group on the left I had a jerk of the trigger or maybe jerk on the trigger.

Troy

[Alan550]

I'm shooting a 9X23 for some of the reasons that longbarrel mentioned, speed for mover lead, cheaper to shoot than a .40 or bigger. One of the main reasons I shoot that caliber is that the 1911 was designed around an OAL of 1.250 and the 9X23 does that with a tapered case. So in essence, you're stuffing a smaller bullet into a larger hole. Makes for reliable feeding and easier extraction, IMHO. The 9mm has a much shorter OAL and takes some really tough fine-tuning to get reliable feeding sometimes once the shroud and comp are added. 115-125 is pretty much the average that you'll see out there, whether it's a 38 Super, 38TJ, 9X23 or Super Comp in Open Class. Accuracy is the first thing that matters, then go for the best velocity for the mover. Less travel time to the mover target means a small error in aiming isn't compounded by the time of bullet travel.

Alan~^~

[Bafaction]

I'm shooting a 9X23 for some of the reasons that longbarrel mentioned, speed for mover lead, cheaper to shoot than a .40 or bigger. One of the main reasons I shoot that caliber is that the 1911 was designed around an OAL of 1.250 and the 9X23 does that with a tapered case. So in essence, you're stuffing a smaller bullet into a larger hole. Makes for reliable feeding and easier extraction, IMHO. The 9mm has a much shorter OAL and takes some really tough fine-tuning to get reliable feeding sometimes once the shroud and comp are added. 115-125 is pretty much the average that you'll see out there, whether it's a 38 Super, 38TJ, 9X23 or Super Comp in Open Class. Accuracy is the first thing that matters, then go for the best velocity for the mover. Less travel time to the mover target means a small error in aiming isn't compounded by the time of bullet travel.

Alan~^~

Sorry to but in but can a 9x23 shell be used in a 38 super gun, I am shooting super comp at the moment and I use lead 122fp and I am acheiving a group of 1.25 - 1.5" at 50 yards. It is a lot cheaper for me to use lead over jacketed.

[Alan550]

The 9X23 will probably chamber & fire in a Super, but shouldn't be done. The Super has a "semi-rim" diameter of ~.406 while the 9X23 head diameter is only ~.388. Along with the other case dimension differences, it's probably not a good idea to interchange the 2 calibers without some tuning of the extractor, etc. and only then as a last resort if you can't get the Super brass. OAL on both will run about the same as case length is .900 for both. The 9X23 was originally designed from a .223 rifle case trimmed to .900 with a 9mm bullet seated. That allows for more pressure (55,000)to be safely run in it as compared to the Super (35,000).

You can also fire a 9X19 in either gun, as the extractor will hold it against the breech face, but why?

Just re-read your post and you're running the Super Comp, so here are the differences. Super Comp: Rim diameter = ~.388, Extractor groove = ~.328, Rim thickness ~ .046. The 9X23 measurements are: Rim diameter = ~.388, Extractor groove =~.322, Rim thickness = ~.046, so as you can see the Super Comp is a pretty close match on the back end, but the 9X23 is a tapered case and the Super Comp is straight-walled.

Again, it can be done, but why?

YMMV

Alan~^~

[Flexmoney]

Sorry to but in...

No worries...at all.

This is just a very general discussion. I was hoping we'd get all kinds of comments and questions.

[Flexmoney]

So...

I have a belief that most auto are probably using the extractor to locate the case...moreso than the chamber.

How about AP guns?

What are some preferences to how the chambers are cut?

[Action Pistolero]

Flex,

I have been thinking about this speed of sound thing for a while. I found this webpage. www.aerospaceweb.org/design/scripts/atmosphere/ I don't know how to do links so maybe you could help me out.

This webpage allows you to plug in velocity and your alitude. It will give you the speed of sound at your altitude.

My theory is that you either have to stay above the speed of sound or stay below it. I remember seeing a show about Chuck Yeager and the X-1. One of the problems they encountered was that as they approached the speed of sound the X-1 would shudder and go out of control. That got me thinking about bullets.

My velocity is 1150 fps. The speed of sound at my elevation is 1106. The bullet passes through the speed of sound in the barrel so the bullet is stabilized. Now, the question is, does the bullet remain above the speed of sound by the time it impacts the target at 50 yards? I really don't know. The only way to tell the velocity is to shoot across the chronograph. I could probably shoot across the skyscreens at that distance but there is a chance of hitting something valuable. I suppose you could find a chart somewhere that would tell you what the velocity is supposed to be but there are so many variables. The accuracy in my gun is there so all it would do is satisfy my curiousity.

As others have said, the minimum caliber is 9mm. The reason to use the smaller caliber has alot to do with the mover but there is also the fact that the larger the caliber the more torque the shooter feels. When the bullet leaves the case and engages the rifling the bullet, of course, starts to spin. In a right hand twist barrel the shooter will feel the gun try to turn clockwise.

The chambers on my guns are as tight as I can make them. Length is a different story. We have all been told that a cartridge should headspace on the case mouth. I tried reaming the chamber of one of my barrels so that the head of the case was aligned perfectly with the end of the hood. I used a dial indicator and had it dead nuts on. I installed the barrel in the gun and tried to chamber a loaded round. It wouldn't chamber. I had to ream it a little more before it would chamber. Now when you drop an empty case in the chamber it goes passed flush with the hood. It seems to me that it is actually headspacing on the extractor.

Any more thoughts?

[gm iprod]

Speed of sound is nominally 1125 fps. http://en.wikipedia.org/wiki/Speed_of_sound

The variables are, altitude, temp, humidity, barometric pressure. But work with 1125.

At 1150fps the bullet has likely dropped to about 1050fps at 50. As far as I can measure the Sierra 115gr JHP (Kevin uses this) has dropped between 20 and 30fps at 10yards. Therefore it is already just below the speed of sound at the first target, thereafter it remains subsonic. I did some testing with my 9mm carbine and Zero 115gr and 125gr JHP. I was trying to duplicate 100yard impact velocities at 10M so I could test bullets on a test medium.

Anyway I found that the bullet speed dropped about 20 - 30 fps per 10yards increase of distance out to 50yards, so i had a base point for working out my expected velocity. I tested the same load at 3, 13 and 23 yards to confirm my estimates. 3 yards is about as close as I like to get to ensure accurate readings. This was with 5 shot groups and I used the average of each group. So I put my chrono out at 10yards and tried loading down. Later I discovered that Sierra had done all this for me. So if you split the difference on the 1200fps and the 1100fps data that Sierra provide you are within 5fps + / - of what I found the hard way. This of course helped me with the handgun loads as I then worked out actual bullet drop every ten yards for my loads (this is another long story).

http://www.exteriorballistics.com/ebexplai...s/pdf/hgy11.pdf

Flex,

Bigger bore bullets. Your original question.

You can easily find 135gr 140gr 150gr 155gr 165gr and 180gr Projectiles for 40cal. My testing of the 135gr Noslers at about 1000fps in a handgun was less than brilliant accuracy at 50. Great up to 25y, but it just would not stay accurate enough, (only tested with one handgun that otherwise offered excellent accuracy at 50Y). But in the Carbine at 1450fps they were great all the way to 100y. So I am not sure if it is the length or not. 155gr SWC were the lightest we were happy with when slowed off in rifle or handgun. That makes them going at about the same speed as a 38Spl with 150gr SWC (850fps). So the mover lead would be about the same as the revolver guys would use. We had a guy here in NZ who shot a lot of IPSC with 210gr 40Cal at major and he sometimes shot them in AP. He shot pretty well and the gun was plenty accurate with those things. Plates went down real quick.

My 38Super Metallic gun prefers 115gr but I like the softness of the 125gr. Both bullets group well under 2" at 50y so when I shot an 8 it is not the load. Lead is simple with 115gr or 125gr with an Metallic sight gun. Edge of x, edge of 10 ring, edge of 8 ring & edge of target. I bet it is within 2" of what you want at 25y.

38Super, TJ, 9x23 etc. FOR OPEN OR METALLIC SIGHTS, if you are building a purpose built gun.

Whatever floats your boat.

BUT in my book 9mmx19, 38Super and SuperComp are the sensible ways to go. Next 9x23, then a ways back to 357Sig and the rest.

It will be no problem building an accurate enough handgun in all the calibres, just throw enough money at it, but the brass availability will heavily influence what you will want to get. In your case I would get a gun built in 9x19. You own a few I am sure.

If getting a used gun, lean towards 9x19 and the 38Super / SuperComp. More of them around for a starter

9x23, (ask Kevin A) can be a difficult proposition from time to time. I like the cartridge, but brass here is amazinginly expensive, so much so that if you ever head this way and have to bring it you will want it back and badly. Brass is also only made by two manufacturers and there is very limited supply on factory ammo. Kevins gun is obscenely accurate so the cartridge is fine.

The 9mm / 38calibe projectiles just work best for the AP matches. Bullet weight v's diameter just suit the match. The main thing is the lower PF. 120 is so easily achieved with fairly light but stable bullets, and the recoil is easy to manage with the weight and design of many of our handguns.

[goneracin]

I posted this pic in another thread a long time ago, but I think its a really cool pic, and shows what happens to things as they pass through supersonic. If you look, there are some pretty wild standing waves in front of the tail section, and under the plane. This plane was right under super sonic speed, so this is what would happen to any projectile at speeds nearing SS

Having said that, Im sure Kevins stuff is passing through the barrier from 35, and 50 at least, and it doesnt seem to hurt him at all so maybe I am over thinking this a little...

[kar45]

I'm shooting a 9X23 for some of the reasons that longbarrel mentioned, speed for mover lead, cheaper to shoot than a .40 or bigger. One of the main reasons I shoot that caliber is that the 1911 was designed around an OAL of 1.250 and the 9X23 does that with a tapered case. So in essence, you're stuffing a smaller bullet into a larger hole. Makes for reliable feeding and easier extraction, IMHO. The 9mm has a much shorter OAL and takes some really tough fine-tuning to get reliable feeding sometimes once the shroud and comp are added. 115-125 is pretty much the average that you'll see out there, whether it's a 38 Super, 38TJ, 9X23 or Super Comp in Open Class. Accuracy is the first thing that matters, then go for the best velocity for the mover. Less travel time to the mover target means a small error in aiming isn't compounded by the time of bullet travel.

Alan~^~

Sorry to but in but can a 9x23 shell be used in a 38 super gun, I am shooting super comp at the moment and I use lead 122fp and I am acheiving a group of 1.25 - 1.5" at 50 yards. It is a lot cheaper for me to use lead over jacketed.

Bafaction, what diameter are your 122FP's, and is it a copy of the old Hornady Air Force bullet? What powder do you use for these 1.25" groups? Thanks, Kirby

[BPiatt]

If I were in the spot to start from scratch, I'd build a 9mm gun.

1. Bullets and Brass are the least expensive.

2. Accuracy is as good as any other caliber. (Mine shoots 1" at 50yds)

3. Function (feed/extraction) is not an issue.

4. If you wanted to buy factory ammo, most any location has 9mm.

(except for counties like Italy where 9mm is illegal)

[gm iprod]

Bruce,

We discussed exactly this some weeks ago and most of us agreed that if we were doing it all from scratch we would probably go 9mm as well.

When I got started here nearly everyone was running 38Super for both IPSC and AP so we just followed along, another thing was we could all get good quality magazines for Super but had real issues getting decent 9mm. A few guys tried and it just did not fly. But now we have three or four manufacturers of decent 9mm.

The Club I shoot at has two or three Kimber 1911 Metallic guns in 9mm configuration specifically for AP, so that we don't have to buy expensive ammo. Any good quality 9mm ammo will work fine.

I just laid my sticky paws on an 9mm 1911 to horse around with.

[BPiatt]

I agree with the magazine issues.

I have found the Metalform magazine designed and sold by Springfield Armory is the best feeding, single stack, 9mm magazine on the market.

Instead of having the spacer in rear, they've scalloped the front of the mag and made the tip of the scallop into a little feed ramp.

[gm iprod]

I saw those when TGO had them at the BC sometime around 2003??? maybe later.

I liked that idea front the get go, I just wish I had thought of it. I actually had a Springfield loaded 9mm with those and they are awesome, unfortunately they are difficult to get here, more unfortunately I was talked into selling that handgun to pay for my open gun in 2005. I will be back in the US in May and will try and scrounge some then for my project. I think that the spacer / ramp built at the front is a better idea, it would appear to smooth out the angle for the short 9mm round to get up to the chamber.

[BigDave]

Why not a 40/10mm bullet? Not accurate enough? Too slow for the mover? What about a 0.400 bullet at 135g? Does it get too short and stubby to have enough bearing surface (to sit nice in the brass? to engage the barrel...throat...rifling?)

.40 in and of itself isn't really an issue. My personal belief after shooting this for a few years is that the Mover helps you decide your load. More or less, anything under 1000 fps and you're making things difficult, especially for iron sighted guns. Why? Under 1000 fps, your 20 yd lead is near the outside edge and the 25 is off the target. Not too much of an issue on an Open gun with a Mover base, but try that with an iron sighted blaster.

I shot a 135 gr Nosler at the suggestion of BE at 1025 fps. VERY SOFT. The load was more accurate than I could make use of. And, I know that BE used this very thing at the Cup and shot at least mid/high 1800's with that setup. Having said that, if .400 had any kind of advantage, I think the big boys would switch. They haven't. BUT, for local matches, if you shoot a .40 Major load in USPSA, just drop a 135 head on that same charge and come play. Plenty of load for a local match. I shot that way for the first 4 years.

I did have my 6" gun built in .38 Super for the '06 Cup. IME, .the .355 heads group better, but you don't need to believe me.

[Flexmoney]

Thanks, Dave.

That brings up a question...

What about power factor? Would anybody avoid shooting a 138+pf load? Funky recoil impulse? Dot/sight tracking issues?

[kimmbeckwith]

Unless you are shooting an existing gun compesated for that load, it would be a disadvantage. If this power factor produced extra recoil or muzzle flip why would you use that load. I did shoot next to some people shooting major loads at one of our local matches and it was very distracting, so your shooting buddies on the line might be a little upset with you.

[Flexmoney]

What is "extra"?

If I am used to shooting 172pf loads all the time, then a 138pf load would be a extra light, right?

(How I got the 138pf number is from the 40cal load Dave posted, 135g x 1025fps...which is still sub-sonic.)

How much true comp action can one expect at 125pf...vs. the comp really being more of a barrel weight?

[kimmbeckwith]

All I know since 1985 (and I made all but two) is that 1150 fps is the best for the mover and all the other matches. Super and 9mm are the most popular ammo with 38 spl next. Heck we even has a 50 cal. acp shot at the nostalga match, but it wasn't very practical.

[Alan550]

Flex, I think you'd be surprised at how much a comp still works at the 120-125 PF level. I have a Marvel Conversion set up for AP, shroud, Stick-Shift and all, and the comp fell off during a practice session once. It was amazing how much muzzle flip increased with a .22 Rimfire round without that comp in place, so no matter what pressure level you run on an AP gun, the comp helps very much! Maybe not to the level that the IPSC guys are accustomed to, but it WORKS. Any muzzle flip is "extra" when you're talking about this game. Just be careful to maintain above the 120 PF. The last thing you want to see on the bulletin board at the Cup is your name listed as being called to the chrono!

Alan~^~

[Flexmoney]

Flex, I think you'd be surprised at how much a comp still works at the 120-125 PF level. I have a Marvel Conversion set up for AP, shroud, Stick-Shift and all, and the comp fell off during a practice session once.

Ahhhh, but how does it work?

I suggest it works...effectively...as a barrel weight, and not so much by comp action. Crazy?

[BigDave]

Well, most folks are using fast powders in 9x guns. Stuff like HP38, N320, WSL and Titegroup. We all know that those loads don't make a lot of gas as compared to their slower burning cousins. Regardless, Open shooters have have had had ported compensators for a long time because they offer some advantage I've never really thought of it, but it is probably a combination of simple weight on the muzzle and the force of the gas on the ports/baffles.

Maybe a smith will chime in here?

[Flexmoney]

All I know since 1985 (and I made all but two) is that 1150 fps is the best for the mover and all the other matches. Super and 9mm are the most popular ammo with 38 spl next. Heck we even has a 50 cal. acp shot at the nostalga match, but it wasn't very practical.

Kim,

I'm not disagreeing with you. I'm just trying to stimulate some discussion.

[BigDave]

What is "extra"?

If I am used to shooting 172pf loads all the time, then a 138pf load would be a extra light, right?

Extra, in terms of PF, is probably 4-5 things down on the list of load criteria behind load accuracy, loading/cycling reliability, and a few others.

But, to your point, why manage any more recoil and sight movement than you have to? This game really is about shooting sub 4" groups while on the clock, it really is. Drop one into the 8-ring, much less out of the X-ring on the paper stages, and you're fighting for 2nd place instead of the 'Cup. Miss a plate and you're probably out of the top 10, or worse.

Like anything else, do only what you need to. That, for me, includes not dealing in any extra PF I don't have to when all other things are working as I intend.